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Age-related reduction of telomeric DNA sequences contributes to mitotic catastrophe and genetic instability, which in turn play major roles in the increased risk of developing cancer. Human B-cells from patients with Fanconi's anemia (FA), ataxia-telangiectasia (AT), Bloom syndrome (BS), and xeroderma pigmentosum (XP) syndromes, causing premature aging and predisposition to neoplasia, were studied for telomere dynamics and mitotic catastrophe, including the frequency of endoreduplication and structural abnormalities. We hypothesized that somatic cells affected by these syndromes have shortened telomeres and down-regulation of telomere repeat binding factor 2 (TRF2). Using conventional and molecular cytogenetic techniques such as quantitative fluorescence in situ hybridization (Q-FISH), we compared patients' cells to cells from age- and sex-matched individuals. The frequency of metaphases with mitotic catastrophe and telomeric associations was significantly higher in FA, BS, and AT cells than in controls, XP being within normal limits. All B-cells (patients and controls) were telomerase positive. Q-FISH showed less telomeric DNA in patient cells compared with controls. However, one control also showed reduced telomeric DNA and increased mitotic catastrophe, with XP cells showing decreased aberrations compared to other syndromes. Western blot analysis of TRF2 showed reduced levels in AT, BS, FA, and one control group. XP cells showed levels of TRF2 protein, similar to controls. From this, we conclude that genetic instability is caused by loss of telomeric DNA. A reduction of telomeric DNA is, therefore, responsible for genetic instability and could be an important factor in causation of or predisposition to develop cancer in these syndromes.

Human neoplasms are heterogeneous for a variety of biological properties that include invasion and metastasis. The presence of a small subpopulation of cells with a highly metastatic phenotype has important clinical implications for diagnosis and therapy of cancer. For this reason, it is important to develop an animal model for the selection and isolation of metastatic variants from human neoplasms and for testing the metastatic potential of human tumor cells.

There is a considerable amount of cytogenetic data available to support the statements that (1) cancer is a genetic disease; (2) most cancers are monoclonal in origin; (3) tumor cells are more genetically unstable than normal cells; (4) the genetic instability may be inherited, acquired, or both during the lifespan of the individual tumor; (5) tumor metastasis is a nonrandom, controlled process, and clonal in origin; (6) malignant tumors are genetically heterogeneous and contain multiple subpopulations that may differ in their biological properties; (7) some tumors might be difficult to treat successfully because of their resistant nature; and (8) tumor cells may acquire resistance because of gene amplification. For these reasons it is extremely important to study the biology of malignant tumor cells in order to determine their effective treatments and control this dreadful disease.

A new cell line designated 584A2 has been recently established from a patient with squamous cell carcinoma of the larynx. Cytogenetic analysis of the cell line revealed multiple copies of chromosome 7, as well as a homogeneous staining region (HSR) on one chromosome 7. Since overexpression of epidermal growth factor (EGF) cell surface receptors (EGFr) often occurs in other squamous carcinoma cell lines, it was predicted that 584A2 might overexpress EFGr. This was confirmed by: (1) metabolic labeling, with subsequent immunoprecipitation of EGFr and comparing autoradiographs to a cell line without an HSR and fewer copies of chromosome 7, and (2) performing EGF binding assays with Scatchard analysis. Since overexpression of EGFr correlates with an inhibitory effect of EGF on cell culture, the biological effects of EGF on 584A2 were examined in this study. At 5 ng/ml (serum-free medium), EFG stimulated incorporation of [3H] thymidine into trichloroacetic acid-precipitable material compared with controls. Incorporation increased between days 0 to 1 and 1 to 2 days with a 6- to 7-fold maximum. Dose-response studies (0 to 100 ng/ml) indicated maximum incorporation (6- to 7-fold) occurred between 0.1 ng/ml and 1.0 ng/ml. Cell growth was monitored over 7 days and, during this time, 5 ng/ml EGF produced a 10- to 12-fold increase in absolute cell numbers when compared with controls. We concluded that, unlike other squamous carcinoma lines with elevated EGFr, EGF stimulates rather than inhibits 584A2 cell proliferation.

The integrins are a family of integral membrane receptors that participate in binding to various extracellular and cell surface proteins during adhesion, migration, and homing of normal and neoplastic cells. In this study, we characterized the involvement of integrins in mediating the growth of an adhesion-dependent gastric adenocarcinoma line, ST2. This line was distinguished and selected for study based on its inability to grow when suspended in soft agar or plated on poly(2-hydroxyethyl methacrylate)-coated dishes. ST2 cells arrested in G0/G1 of the cell cycle when deprived of adhesion to substrate. Using purified matrix components, collagen was found to be highly active in promoting β1 integrin-mediated cell attachment and spreading. Subsequent to spreading on collagen, the cells were released from G0/G1 block and progressed into S phase. Monoclonal antibodies to α2 or β1 integrin blocked the reinduction of both cell spreading and entry into S phase. These studies suggest that during the metastatic process, integrin receptor interaction with the insoluble matrix may be an important step leading to proliferation of some tumors.

Conclusion: We established a new human pancreatic adenocarcinoma cell line, MDAPanc-28. Studies on this new line indicate that it expresses both acinar and ductal gene products suggesting that the patterns of gene expression in the pancreatic adenocarcinoma from which this cell line arose have features similar to those of the protodifferentiated cells hypothesized by Rutter and his colleagues for the developing pancreas(1,2). Background: The cell line arose from a tumor that, like most pancreatic adenocarcinomas, was ductal on the basis of its histological appearance. Methods: Once the cell line was established in culture, they were subjected to cytogenetic analysis and tested for their ability to grow in nude mice. RNA from the cells was analyzed by Northern blot analysis and PCR of reverse transcribed cDNA for the expression of both acinar and duct cell gene products. DNA was analyzed for the presence of mutated K-ras at codon 12. Results: The cell line expressed trypsin and ribonuclease RNA, which are considered to be acinar cell markers, and carbonic anhydrase II (CAII), which is considered to be a duct-cell markers. The histological appearance of xenografts in nude mice was similar to that of the tumor from which the cell line was established. The chromosome number varied between 46 and 60.

The karyotypic abnormality t(14;18)(q32;q21) is reported to occur in 75% of follicular lymphomas. This translocation results in the rearrangement of a putative oncogene bcl-2. which resides at chromosome 18 band q21 (the 18q21 gene). Using two human genomic DNA fragments cloned from the chromosome 18 band q21 as probes, we analyzed 65 uncultured human lymphoma samples by the Southern blot technique. The 18q21 gene was rearranged in 18 of 26 (69%) follicular lymphomas, 3 of 5 (60%) follicular lymphomas transformed to large cell lymphomas, 8 of 20 (40%) diffuse large cell lymphomas (DLCLs), and 2 of 7 (29%) small noncleaved cell lymphomas (SNCs). Our analysis detected rearrangement of the 18q21 gene in 10 of 13 (77%) cases in which the t(14;18)(q32;q21) translocation was found by cytogenetic techniques. Our analysis also proved helpful in difficult karyotyping situations: (a) identifying the donor chromosome fragment as chromosome 18 band q21 in 4 of 9 (44%) cases that cytogenetically displayed a 14q-l- chromosome of unknown origin, and (b) identifying a rearrangement of chromosome 18 band q21 in 12 of 18 (67%) cases that cytogenetically yielded no cells in metaphase. We also demonstrated three cases of submicroscopic rearrangement of the 18q21 gene. In our studies, patients with DLCLs and rearrangement of the 18q21 gene had a significantly higher incidence of extranodal involvement when compared with patients with DLCLs and no 18q21 gene rearrangement (P = 0.03).

Karyotypic abnormalities were studied in multiple myeloma and were correlated with clinical features. Among 115 evaluable patients, 46% had an abnormal karyotype. Trisomy 3, 5, 9, and 15 and monosomy 13 and 16 were the most common clonal abnormalities. Translocations described previously in other B cell malignancies occurred in nine patients, including four with t(8;14)(q24;q32) translo-cations. The association of all t(8;14) abnormalities with IgA protein type suggested a pathogenetic relationship between a specific karyotypic abnormality and myeloma protein type. Hypodiploidy occurred mainly in patients with only Bence Jones protein, was associated with resistance to therapy, and justified the early consideration of investigational therapies.1988 by Grune & Stratton, Inc. 0006-4971/88/7102-0026$ 3.00/0

Chromosome analysis in the cultured peripheral blood lymphocytes of multiple endocrine adenomatosis (MEA-II) patients and their siblings demonstrated a preponderance of higher frequency of metaphases with chromosome and chromatid type abnormalities (average, 11.0%) as compared to controls (average, 3.8%). Our preliminary data suggest that MEA-II patients exhibit some degree of chromosome instability.(JAMA 1981;246:2046-2048)

Surface marker and gene rearrangement data have supported various hypotheses about the origin of the malignant cell in Hodgkin's disease. Cytogenetic data about this disorder, however, are very scanty. To determine if any chromosomal abnormalities that could add further information to this controversial point are present, we studied tumor samples from 49 patients. Abnormal metaphases were obtained in 18 cases. The most common breakpoints were in 11q23, 14q32, 6q11-21, and 8q22-24. These are common breakpoints in lymphoma and raise the possibility that the malignant cell in Hodgkin's disease may be derived from a lymphocyte. The 11 q23 breakpoint is also seen in t(4;11) and t(9;11), which is typical of a type of childhood B-cell acute lymphoblastic leukemia characterized by the presence of aberrant myeloid and monocytic markers. Myeloid and monocytic markers are common in Reed-Sternberg cells.

The Giemsa banding pattern of the karyotype of Neotoma micropus is compared with the banding patterns of seven other rodent species that are progressively more distantly related to N. micropus. Results of comparisons imply that there is a tendency for arrangement of genetic material on chromosomes to be conserved. Results also lend support to systematic inferences based on characters of the glans penis and suggest that the type of approach employed here may be useful in characterizing phylogenetic relationships between genera, tribes, subfamilies, and families of rodents.